Cytokine accumulation in stored red cell concentrates: effect of buffy-coat removal and leucoreduction

Comparison of Two Alternative Procedures to Obtain Packed Red Blood Cells for β-Thalassemia Major Transfusion Therapy

β-thalassemia major (βTM) patients require frequent blood transfusions, with consequences that span from allogenic reactions to iron overload. To minimize these effects, βTM patients periodically receive leucodepleted packed red blood cells (P-RBCs) stored for maximum 14 days. The aim of this study was to compare two alternative routine procedures to prepare the optimal P-RBCs product, in order to identify differences in their content that may somehow affect patients’ health and quality of life (QoL). In method 1, blood was leucodepleted and then separated to obtain P-RBCs, while in method 2 blood was separated and leucodepleted after removal of plasma and buffycoat. Forty blood donors were enrolled in two independent centers; couples of phenotypically matched whole blood units were pooled, divided in two identical bags and processed in parallel following the two methods. Biochemical properties, electrolytes and metabolic composition were tested after 2, 7 and 14 days of storage. Units prepared with both methods were confirmed to have all the requirements necessary for βTM transfusion therapy. Nevertheless, RBCs count and Hb content were found to be higher in method-1, while P-RBCs obtained with method 2 contained less K⁺, iron and storage lesions markers. Based on these results, both methods should be tested in a clinical perspective study to determine a possible reduction of transfusion-related complications, improving the QoL of βTM patients, which often need transfusions for the entire lifespan.

The emerging role of red blood cells in cytokine signalling and modulating immune cells

For many years red blood cells have been described as inert bystanders rather than participants in intercellular signalling, immune function, and inflammatory processes. However, studies are now reporting that red blood cells from healthy individuals regulate immune cell activity and maturation, and red blood cells from disease cohorts are dysfunctional. These cells have now been shown to bind more than 50 cytokines and have been described as a sink for these molecules, and the loss of this activity has been correlated with disease progression. In this review, we summarise what is currently understood about the role of red blood cells in cytokine signalling and in modulating the activity of immune cells. We also discuss the implications of these findings for transfusion medicine and in furthering our understanding of anaemia of chronic inflammation. By bringing these disparate units of work together, we aim to shine a light on an area that requires significantly more investigation.

IL8 and IL16 levels indicate serum and plasma quality

BACKGROUND

Longer pre-centrifugation times alter the quality of serum and plasma samples. Markers for such delays in sample processing and hence for the sample quality, have been identified.

METHODS

Twenty cytokines in serum, EDTA plasma and citrate plasma samples were screened for changes in concentration induced by extended blood pre-centrifugation delays at room temperature. The two cytokines that showed the largest changes were further validated for their "diagnostic performance" in identifying serum or plasma samples with extended pre-centrifugation times.

RESULTS

In this study, using R&D Systems ELISA kits, EDTA plasma samples and serum samples with a pre-centrifugation delay longer than 24 h had an IL16 concentration higher than 313 pg/mL, and an IL8 concentration higher than 125 pg/mL, respectively. EDTA plasma samples with a pre-centrifugation delay longer than 48 h had an IL16 concentration higher than 897 pg/mL, citrate plasma samples had an IL8 concentration higher than 21.5 pg/mL and serum samples had an IL8 concentration higher than 528 pg/mL.

CONCLUSIONS

These robust and accurate tools, based on simple and commercially available ELISA assays can greatly facilitate qualification of serum and plasma legacy collections with undocumented pre-analytics.

Anemia and Transfusion in Critical Care

Objective:

The objective of this report is to review the physiology and management of anemia in critical care. Selected publications on physiology and transfusion related to anemia and critical care, including the modern randomized trials of conservative versus liberal transfusion policy, were used. Anemia is compensated and tolerated in most critically ill patients as long as oxygen delivery is at least twice oxygen consumption. There are risks to blood transfusion which can be minimized by blood banking practice. The availability of cultured red cells may allow correction of anemia without significant risk. The benefit of transfusion in anemia must be weighted against the risk in any specific patient.

Conclusion and Recommendation:

In a criticially ill patient, anemia should be managed to avoid oxygen supply dependency (oxygen delivery less than twice comsumption) and to maintain moderate oxygen delivery reserve (DO2/VO2 > 3).

Quality control of buffy coat removed red cell concentrates--a Croatian experience

OBJECTIVES

Results are presented of the statistical quality control of red cell concentrate buffy coat removed in additive solution (RCC/BC/AS) and red cell concentrate buffy coat removed and leucoreduced in additive solution (RCC/BC/LR/AS) produced at the Croatian Institute of Transfusion Medicine during an 8-year period (2005-2012). The aim was to assess quality conformity of these products with specified requirements, as well as the suitability and justification of current regulations on the minimal quality requirements.

METHODS

The measurements of all the study parameters of the products analysed are expressed using descriptive statistics and graphs showing the distributions of observed parameters.

RESULTS

In RCC/BC/AS, the mean (± SD) volume was 279 ± 17 mL; haematocrit, 0.60 ± 0.03 L L(-1); haemoglobin content, 55 ± 5 g; leucocyte count, 0.65 ± 0.41 × 10(9); and haemolysis at expiry date, 0.16 ± 0.13%. In RCC/BC/LR/AS (post-production filtration), the mean (± SD) volume was 255 ± 14 mL; haematocrit, 0.60 ± 0.02 L L(-1); haemoglobin content, 51 ± 4 g; leucocyte count, 0.11 ± 0.16 × 10(6); and haemolysis at expiry date, 0.11 ± 0.07%. In RCC/BC/LR/AS (inline filtration), the mean (± SD) volume was 254 ± 15 mL; haematocrit, 0.61 ± 0.02 L L(-1); haemoglobin content, 51 ± 5 g; leucocyte count, 0.04 ± 0.06 × 10(6); and haemolysis at expiry date, 0.16 ± 0.10%. The standards were just met for leucocyte count in RCC/BC/AS (90%), whereas for all other parameters satisfactory results were obtained in at least 99% of products analysed. Total incidence of bacterial contamination was 0.23% for all products.

CONCLUSION

Results of the RCC/BC/AS and RCC/BC/LR/AS quality control showed very high conformity with the specified requirements in the majority of study parameters, suggesting that the current requirements could be redefined and improved at the institutional level.

Cytokine concentration in stored canine erythrocyte concentrates

OBJECTIVE

To evaluate the effect of leukoreduction (LR) as compared to standard nonleukoreduced (NLR) units on cytokine concentrations in canine erythrocyte concentrates during regular storage time.

DESIGN

Randomized, experimental study.

SETTING

University teaching hospital.

ANIMALS

Ten random-source research dogs.

INTERVENTIONS

One unit of whole blood was collected from each dog and randomized to standard processing (NLR, n = 5) or prestorage LR (n = 5). All units were stored at 4°C. Samples were aseptically collected from each unit weekly for 5 weeks. On day 35, 1 mL of blood was collected from each unit and submitted for aerobic culture.

MEASUREMENT AND MAIN RESULTS

An ELISA assay was used to analyze the concentrations of IL-1β, IL-8, TNF-α, and IL-10. There were no significant effects of either group or storage time for IL-1β, IL-10, or TNF-α. IL-8 concentration was significantly increased over the storage period in NLR units, and was significantly higher compared to LR units on days 28 and 35. Aerobic culture was negative on all units.

CONCLUSIONS

This study demonstrated a marked, storage time-dependent accumulation of IL-8 in canine erythrocyte concentrates. Prestorage LR attenuated the accumulation of IL-8. This chemokine may contribute to the proinflammatory effects of transfusion of stored erythrocyte concentrates.

Impact of perioperative allogeneic and autologous blood transfusion on acute wound infection following total knee and total hip arthroplasty

BACKGROUND

Patients undergoing total hip or knee arthroplasty frequently receive blood transfusions. The relationship between transfusion and the risk of infection following total joint arthroplasty is unclear. In this study, we sought to examine the impact of allogeneic and autologous transfusion on the risk of acute infection following total hip and total knee arthroplasty.

METHODS

We performed a retrospective study of consecutive primary total knee arthroplasties and total hip arthroplasties. Patients who had a reoperation for suspected infection within three months after the arthroplasty were identified. Differences in risk factors were assessed across transfusion groups: no transfusion, autologous only, and allogeneic exposure (allogeneic with or without additional autologous transfusion). Backward-stepwise logistic regression analysis was used to compare reoperations (as outcomes) between cases with and those without allogeneic exposure. Prespecified covariates were body mass index, diabetes, an American Society of Anesthesiologists (ASA) score of >2, preoperative hematocrit, and total number of units transfused perioperatively.

RESULTS

We identified 3352 patients treated with a total hip or knee arthroplasty (1730 total knee arthroplasties and 1622 total hip arthroplasties) for inclusion in the study. Transfusion was given in 1746 cases: 836 of them had allogeneic exposure, and 910 had autologous-only transfusion. There were thirty-two reoperations (0.95%) for suspected infection. Between-group risk-factor differences were observed. The mean age and the rates of diabetes, immunosuppression, ASA scores of >2, and bilateral surgery were highest in the allogeneic group, as were estimated blood loss, surgery duration, and total number of units transfused (p < 0.001). In the unadjusted analyses, the rate of reoperations for suspected infection was higher in the cases with allogeneic exposure (1.67%) than in those without allogeneic exposure (0.72%) (p = 0.013). Autologous-only transfusion was not associated with a higher reoperation rate. However, multivariable logistic regression demonstrated that the total number of units transfused (p = 0.011) and an ASA score of >2 (p = 0.008)-but not allogeneic exposure-were significantly predictive of a reoperation.

CONCLUSIONS

Perioperative allogeneic transfusion was associated with a higher rate of reoperations for suspected acute infection. However, patients with allogeneic exposure had increased infection risk factors. After adjustment for the total number of units transfused and an ASA score of >2, allogeneic exposure was not significantly predictive of a reoperation for infection.

Transfusion begets anemia: the effect of aged blood on hematopoiesis

BACKGROUND

Following trauma, transfusion of aged stored blood is often necessary yet associated with increased morbidity and mortality. Despite blood replacement, many patients have a prolonged anemia requiring further transfusions. The effects of aged blood on bone marrow (BM) hematopoiesis have not been studied, and we hypothesized that stored blood suppresses BM function.

METHODS

Blood from Sprague-Dawley rats was stored for 1, 14, or 28 days with the industry preservative citrate-phosphate-dextrose-adenine-1 (CPDA-1). For in vitro studies, 5% supernatant was incubated with normal rat BM and cultured for erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) colony-forming units. Data were compared with cultures of BM alone, 5% control plasma (negative control), and 12% CPDA-1. For in vivo studies, rats were transfused with stored supernatants (5% estimated blood volume (EBV) over 30 minutes). BM from each recipient was cultured for CFU-E and CFU-GM at 3 hours after transfusion. Data were compared with cultures of BM alone. Difference between groups determined by analysis of variance and Tukey's multiple comparison test.

RESULTS

In vitro exposure to CPDA-1, control plasma, or 1-day supernatant (D1) had no effect on BM growth compared with BM alone. In vitro exposure to 14-day (D14) and 28-day (D28) supernatant significantly suppressed CFU-E by 60% and CFU-GM growth by 71% (both p < 0.05) compared with D1 or medial alone. There were no differences between D14 and D28. In vivo exposure to D14 reduced BM CFU-E and CFU-GM growth by 55% (both p < 0.05) compared with D1 supernatant.

CONCLUSION

Plasma from aged blood adversely affects CFU-E and CFU-GM growth in rats. The effect is not mediated by CPDA-1. Transfusion of aged stored blood may contribute to BM dysfunction in critically ill patients, resulting in persistent anemia and the need for further transfusion. This BM dysfunction may also partly explain the observed increased susceptibility to infection.

The prevention of adverse reactions to transfusions in patients with haemoglobinopathies: a proposed algorithm

BACKGROUND

Transfusion therapy remains the main treatment for patients with severe haemoglobinopathies, but can cause adverse reactions which may be classified as immediate or delayed. The use of targeted prevention with drugs and treatments of blood components in selected patients can contribute to reducing the development of some reactions.The aim of our study was to develop an algorithm capable of guiding behaviours to adopt in order to reduce the incidence of immediate transfusion reactions.

MATERIALS AND METHODS

Immediate transfusion reactions occurring over a 7-year period in 81 patients with transfusion-dependent haemoglobinopathies were recorded. The patients received transfusions with red cell concentrates that had been filtered prestorage. Various measures were undertaken to prevent transfusion reactions: leucoreduction, washing the red blood cells, prophylactic administration of an antihistamine (loratidine 10 mg tablet) or an antipyretic (paracetamol 500 mg tablet).

RESULTS

Over the study period 20,668 red cell concentrates were transfused and 64 adverse transfusion reactions were recorded in 36 patients. The mean incidence of reactions in the 7 years of observation was 3.1‰. Over the years the incidence gradually decreased from 6.8‰ in 2004 to 0.9‰ in 2010.

DISCUSSION

Preventive measures are not required for patients who have an occasional reaction, because the probability that such a type of reaction recurs is very low. In contrast, the targeted use of drugs such as loratidine or paracetamol, sometimes combined with washing and/or double filtration of red blood cells, can reduce the rate of recurrent (allergic) reactions to about 0.9‰. The system for detecting adverse reactions and training staff involved in transfusion therapy are critical points for reliable collection of data and standardisation of the detection system is recommended for those wanting to monitor the incidence of all adverse reactions, including minor ones.

Influence of Red Blood Cell Storage Time on Clinical Course and Cytokine Profile in Septic Shock Patients

BACKGROUND: Previous investigations have suggested beneficial effects of fresh versus stored red blood cell transfusion in critically ill patients. The present study investigates the effects of red blood cell storage time on the clinical course and hemodynamic and laboratory parameters in patients with septic shock. PATIENTS AND METHODS: 18 patients with septic shock received 2 erythrocyte units stored for ? 7 days (n = 8) or > 7 days (n = 10). The sequential organ failure assessment (SOFA) score was calculated for 7 days. Hemodynamic parameters (cardiac index, extravascular lung water) were determined using transpulmonary thermodilution. Laboratory parameters (lactate, base excess, C-reactive protein, procalcitonin, IL-1Β, IL-6, TNF-α, sVCAM-1, sICAM-1) were monitored before and 1, 3, 6, 12, 24, and 48 h after transfusion. The Mann-Whitney-U test and Neumann test were used for group comparison and trend assessment, respectively. RESULTS: We failed to observe significant differences with respect to SOFA scores between patients receiving fresh or stored erythrocytes. However, a significant trend towards an improvement in the SOFA score was found in the group receiving fresh erythrocytes (p < 0.01). No significant differences in hemodynamic or laboratory parameters were found between both groups. CONCLUSION: While the present findings do not provide clear-cut evidence supporting beneficial effects of fresh red blood cells in septic shock, they warrant larger randomized studies to confirm or refute such effects.

Fresh red blood cell transfusion and short-term pulmonary, immunologic, and coagulation status: a randomized clinical trial

RATIONALE

Transfusion-related pulmonary complications are leading causes of morbidity and mortality attributed to transfusion. Observational studies suggest an important role for red blood cell (RBC) storage duration in these adverse outcomes.

OBJECTIVES

To evaluate the impact of RBC storage duration on short-term pulmonary function as well as immunologic and coagulation status in mechanically ventilated patients receiving RBC transfusion.

METHODS

This is a double-blind, randomized, clinical trial comparing fresh (≤5 d of storage) versus standard issue single-unit RBC transfusion in adult intubated and mechanically ventilated patients. The primary outcome is the change in pulmonary gas exchange as assessed by the partial pressure of arterial oxygen to fraction of inspired oxygen concentration ratio (ΔPa(O(2))/Fi(O(2))). Secondary outcomes include changes in immune and coagulation status.

MEASUREMENTS AND MAIN RESULTS

Fifty patients were randomized to receive fresh RBCs and an additional 50 patients to standard issue RBCs. Median storage age was 4.0 days (interquartile range, 3.0-5.0) and 26.5 days (interquartile range, 21.0-36.0) in the fresh RBC group and standard issue RBC group, respectively. No differences were noted in the primary outcome of ΔPa(O(2))/Fi(O(2)) (difference between the mean ΔPa(O(2))/Fi(O(2)) in the standard issue RBC group vs. the fresh RBC group, -11.5; 95% confidence interval, -35.3 to 12.3; P = 0.22). Similarly, no significant differences were noted in markers of immunologic or coagulation status.

CONCLUSIONS

In this randomized clinical trial, no differences were noted in early measures of pulmonary function or in immunologic or coagulation status when comparing fresh versus standard issue single-unit RBC transfusion. Clinical trial registered with ClinicalTrials.gov (NCT00751322).

Acute exacerbation of subclinical pulmonary fibrosis after red blood cell transfusion: a case report

BACKGROUND

Red blood cell (RBC) transfusion is associated with lung injury in susceptible hosts, although many cases do not meet criteria for transfusion-related acute lung injury. Patients with underlying pulmonary fibrosis can exhibit precipitous deteriorations in respiratory status of unknown etiology defined as acute exacerbations due to superimposed lung injury syndrome. It is unclear whether RBC transfusion is associated with acute exacerbation of underlying pulmonary fibrosis.

CASE REPORT

We describe a patient who underwent an uneventful elective left total hip replacement but developed anemia postoperatively. Twenty-four hours after transfusion of her fifth nonleukoreduced AS-5 RBC unit, she developed new bilateral airspace infiltrates associated with progressive hypoxemia. These RBC units were 35 to 38 days old. Despite supportive care and diuresis, the patient remained profoundly hypoxemic with infiltrates that progressed to fibrosis.

RESULTS

The patient had mild subclinical lower-lobe predominant interstitial pulmonary fibrosis but developed diffuse bilateral ground glass opacities with areas of consolidation 24 hours after receiving her last RBC unit. Transbronchial biopsy of the right lower lobe showed active organizing pneumonia and underlying interstitial fibrosis, supporting the clinical diagnosis of acute exacerbation of pulmonary fibrosis. The bronchoalveolar lavage showed progressive bloody effluent, consistent with diffuse alveolar hemorrhage, a marker of lung injury. There was no evidence of viral inclusions, fungal elements, pneumocystis, or bacterial organisms.

CONCLUSION

Transfusion of multiple units of aged RBCs was temporally associated with an acute exacerbation and rapid progression of underlying subclinical pulmonary fibrosis.

Generation of neutrophil priming activity by cell-containing blood components treated with pathogen reduction technology and stored in platelet additive solutions

BACKGROUND

Storage of cell-containing blood components such as platelet concentrates (PCs) and red blood cells (RBCs) results in generation of biologically active compounds, many of which may be associated with adverse transfusion events. Priming of the neutrophil oxidase activity is a common characteristic of many of the biologically active compounds found in stored blood. We evaluated the priming activity of pathogen reduction technology (PRT)-treated PCs stored in plasma or platelet additive solution (PAS) and PRT-treated RBCs.

STUDY DESIGN AND METHODS

PCs were collected with Trima or Amicus equipment and were PRT treated with the Mirasol PRT system or the Intercept Blood System. Some units were gamma irradiated. Products were stored in 100% plasma or 35% plasma plus PAS. RBCs were washed and PRT treated before storage. Samples were removed throughout storage and priming of the oxidase activity was measured.

RESULTS

Platelets collected on Trima or Amicus equipment and stored in plasma or PAS demonstrated increasing priming activity during 5 to 7 days of storage. Gamma irradiation, but not PRT treatment with either technology, further enhanced this priming activity. Supernatants of RBCs stored for 42 days induced priming in untreated controls, but not in washed or Mirasol PRT-treated test products.

CONCLUSION

Production of oxidase priming activity increased during storage in all blood products. No significant differences were associated with the collection method, storage in PAS, or PRT treatment. The generation of biologically active compounds, which may serve as an etiology for adverse events, appears to be independent of these processes for collection, storage, and pathogen reduction.

Pilot analysis of cytokines levels in stored granulocyte-colony-stimulating factor-mobilized peripheral blood stem cell concentrates

BACKGROUND

The transfusion of peripheral blood stem cell (PBSC) concentrates is sometimes associated with febrile transfusion reactions. PBSC concentrates contain large numbers of white blood cells, and during storage the levels of soluble cytokines that could cause transfusion reactions may increase.

STUDY DESIGN AND METHODS

Aliquots of granulocyte-colony-stimulating factor (CSF)-mobilized PBSC concentrates from nine healthy subjects were stored in bags at 2 to 8°C for 48 hours. The levels of 19 growth factors and biologic response modifiers were measured in the plasma of PBSC concentrates at 0, 24, and 48 hours of storage using a nested enzyme-linked immunosorbent assay. The same 19 factor levels were also measured in blood plasma from six healthy subjects.

RESULTS

There were no significant differences in the PBSC and plasma levels of soluble interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, which can cause febrile reactions. The levels of TGF-β1, matrix metalloproteinase-8, CCL5/(reduced on activation normal T expressed and secreted), and platelet (PLT)-derived growth factor-AB were significantly greater in PBSCs than in plasma and the level of CCL2/MCP-1 was significantly less in PBSCs. Duration of PBSC storage had no effect on the levels of these five factors. There was a trend for reduced levels of IL-1β, IL-2, IL-7, IL-8, IL-12p70, IL-15, interferon-γ, CD40L, and granulocyte-macrophage-CSF and increased levels of TNF-α and IL-10 levels in PBSC concentrates, but the differences were not significant.

CONCLUSIONS

There was no increase in stored PBSC concentrates of cytokines that have been associated with febrile transfusion reactions; however, the levels of other factors that were likely released by PLTs and granulocytes during the collection process were elevated.

Level of platelet-derived cytokines in leukoreduced red blood cells is influenced by the processing method and type of leukoreduction filter

BACKGROUND

In contrast to the well-documented effect of white blood cells on the quality of red blood cells (RBCs), the effect of platelets (PLTs) has received little consideration. In this study, the PLT content and level of PLT-derived cytokines in RBCs prepared using different types of leukoreduction methods were investigated.

STUDY DESIGN AND METHODS

Buffy coat-poor RBCs and five types of leukofiltered (LF) RBCs, including RBCs prepared with a whole blood (WB) PLT-saving filter, were prepared and stored according to standard blood bank conditions. PLT content was measured on Day 1, and levels of PLT-derived cytokines were measured by enzyme-linked immunosorbent assay at nominated timepoints during 42 days of storage.

RESULTS

The PLT content of leukoreduced RBCs varied widely depending on the processing method and/or leukoreduction filter used, with some types of RBCs containing very low PLT counts while other units contained PLT counts comparable to those of unprocessed WB. The PLT content of RBCs directly influenced the concentration and accumulation of PLT-derived cytokines. Several PLT-derived factors exhibited significant accumulation throughout 42 days of storage. RBCs with high PLT content exhibited concentrations of RANTES (CCL5) and soluble CD40 ligand equivalent to those previously reported to show significant biologic and clinical effects.

CONCLUSION

The PLT content and levels of PLT-derived cytokines in leukoreduced RBCs are influenced by the processing method and types of leukoreduction filters used. It may be inappropriate to consider LF-RBCs prepared with different types of leukoreduction filters as equivalent products based on their differing levels of PLT factors.

Red blood cell supernatant potentiates LPS-induced proinflammatory cytokine response from peripheral blood mononuclear cells

Allogeneic blood transfusion has an immunomodulatory capacity on its recipients through accumulation of immunologically active substances with blood storage, and prestorage leukoreduction reduces many of these mediators. We investigated lipopolysaccharide (LPS)-induced cytokine response of peripheral blood mononuclear cells (PBMCs) exposed to packed red blood cell (PRBC) supernatants from leukoreduced (LR) or non-leukoreduced (NLR) units with variable duration of storage. PRBC units were collected with or without leukoreduction on Day 0 before routine storage. The plasma fraction (supernatant) was isolated from LR and NLR units after 1 day (D1) or 42 days (D42) of storage and exposed to PBMCs versus control media for 24 h, then with LPS for an additional 24 h. Cell supernatants were analyzed for IL-1beta, IL-6, IL-8, IL-10, and TNF-alpha by cytokine bead array. IL-1beta, TNF-alpha, and IL-6 were significantly elevated in PRBC groups versus control. D42 NLR PRBC supernatant significantly increased secretion of IL-1beta and IL-6 compared to D1 NLR PRBC supernatant. LR significantly attenuated the cytokine response of IL-1beta. Thus, PRBC supernatant potentiates proinflammatory LPS-induced cytokine secretion from PBMCs. This response is accentuated with storage duration and partially attenuated with leukoreduction. These findings may partially explain the immune activation seen clinically after blood transfusion.

Length of storage and in vitro immunomodulation induced by prestorage leukoreduced red blood cells

BACKGROUND

The relationship between length of storage of red blood cell (RBC) units and biochemical changes has been well studied, but little is known about the progression of cellular immunomodulative properties in blood recipients. This study aims to quantify in vitro T-cell activation and cytokine release by white blood cells, after incubation with supernatants from leukoreduced RBCs.

STUDY DESIGN AND METHODS

Whole blood cultures were incubated with supernatant from five leukoreduced RBC units stored for 1, 6, 10, 15, 24, and 42 days. Supernatant-induced T-cell activation was evaluated by quantifying CD25 expression. Supernatant-induced cytokine production was determined by measuring interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha levels.

RESULTS

No cytokines were detected in RBC supernatants even after 42 days of storage. However, IL-6 levels in whole blood culture increased significantly when incubated with supernatant from RBC units stored for 1, 6, and 15 days, by factors of 1.7 +/- 0.3, 1.7 +/- 0.3, and 1.4 +/- 0.3, respectively. TNF-alpha levels were significantly decreased on Days 24 and 42 of storage by factors of 0.50 +/- 0.42 and 0.33 +/- 0.21, respectively. IL-10 levels were significantly increased on Days 1 and 42 of storage by factors of 2.3 +/- 1.3 and 3.2 +/- 2.8, respectively. After an initial increase in IL-6 and TNF-alpha production, there was a significant linear decrease in their levels measured from units stored for longer times. No significant changes in CD25 expression were observed over time.

CONCLUSION

Although no cytokines were measured in the supernatants from leukoreduced RBCs, these supernatants exhibited variable immunomodulatory effects related to their length of storage.

Stored red blood cell transfusion induces regulatory T cells

BACKGROUND

Allogeneic blood transfusion mediates immunosuppression in transfused recipients by an unknown mechanism. Regulatory T cells (T(regs)) are suppressive CD4(+)CD25(+)Foxp3(+) cells with a central role in immunosuppression in trauma victims, cancer patients, and transplant recipients. We hypothesized that transfusion-related immunosuppression is, in part, mediated by induction of T(regs), and this induction is attenuated with prestorage leukoreduction and accentuated with prolonged storage.

STUDY DESIGN

Packed red blood cell (PRBC) units were obtained and 50% of PRBCs were leukoreduced (LR) before routine storage for 1 day or 42 days and the supernatant was collected. Normal human peripheral blood mononuclear cells (PBMCs) were exposed to 1-day NLR, 42-day NLR, 1-day LR, or 42-day LR PRBC supernatants or to PRBC storage solution or washed PRBC supernatant +/- anti-CD3 stimulation, and analyzed by flow cytometry for Foxp3(+) T(regs) or CD25(+)-activated T cells. PRBC supernatants and cell culture supernatants were analyzed by immunoassay for interleukin (IL)-1beta, IL-2, IL-4, IL-10, interferon-gamma, tumor necrosis factor-alpha, and transforming growth factor-beta. T(reg) activity was evaluated by suppression assay.

RESULTS

All PRBC groups induced T(regs) compared with control media in anti-CD3-stimulated PBMCs, without alteration by LR or prolonged storage. PRBC supernatant did not alter nonspecific T-cell activation from control media. PRBC-induced T(regs) were suppressive, inhibiting proliferation of T-responder cells. All cytokines measured decreased with storage in LR PRBC units and no cytokines were substantially elevated in cell supernatants exposed to PRBC supernatant. PRBC storage solution did not reproduce the effects of PRBC supernatant, and washed PRBC supernatant attenuated T(reg) induction.

CONCLUSIONS

PRBC supernatant induces T(regs), but this induction is not altered by LR or prolonged storage. This induction appears to be independent of cytokines and is attenuated with washed PRBCs, implicating the plasma fraction.

Clinical effects of different types of red cell concentrates in patients with thalassemia and sickle cell disease

The treatment of thalassemia is still essentially based on continuous transfusion supporting using red cell concentrates (RCC) prepared in different ways. For patients with sickle-cell disorders, either urgent or chronic red blood cell transfusion therapy, is widely used in the management of sickle cell disease (SCD) because it reduces HbS level and generally prevents recurrent vaso-occlusive disease (VOD). Recently, the introduction of pre-storage filtration to remove leukocytes and the use of techniques for multicomponent donation have increased the types of blood components available for transfusion purposes. The clinical effects of different types of blood components in thalassaemic and sickle-cell patients have not been extensively studied so far. We evaluated the impact of the various different blood components currently available on transfusion needs, transfusion intervals and adverse reactions in order to determine which is the most advantageous for transfusion-dependent thalassaemic and sickle-cell patients followed in our centre. We believe that the optimal characteristics of the RCC are aged less than 10 days from time of collection; Hb content greater than 56 g per unit; Hct: 55-60%; volume (including additive) 300 mL+/-20%; leucodepleted to less than 200,000 leukocytes per unit; low cytokine content (achievable by pre-storage filtration carried out between two and 24 hours after the collection); lack of microaggregates (achievable by pre-storage filtration or filtration in the laboratory) and protein content less than 0.5 g per unit for patients allergic to plasma proteins (achievable with manual or automated washing). It is still recommended that the blood transfused should be as fresh as possible, compatible with the centre's product availability and the centre's organisation should be continuously adapted to this aim. We always transfuse blood within 10 days of its collection, respecting Rh and Kell system phenotypes. Pre-storage filtration is strongly recommended, both in order to prevent adverse reactions through the marked leucodepletion (less than 200,000 leukocytes per unit) and for a better standardisation of the final product, including the certainty that the product does not contain clots, an assurance that bed-side filtration cannot give. The RCC should be produced using a method causing as little as possible stress to the red cell membrane. The use of RCC with a high content of Hb (less than 56 g per unit) is strongly recommended, because our study clearly shows that this reduces the number of exposures to donors and the number of accesses to hospital, thus improving the patient's quality of life.

Storage duration and white blood cell content of red blood cell (RBC) products increases adhesion of stored RBCs to endothelium under flow conditions

BACKGROUND

Adherence of red blood cells (RBCs) to vascular endothelium impairs blood flow and decreases oxygen delivery. Although RBCs may be stored for up to 42 days before transfusion under current blood banking guidelines, little is known of how changes to RBCs during storage may affect their adherence properties. The influence of RBC product storage time and white blood cell (WBC) burden on the adherence of RBCs for transfusion to vascular endothelium under conditions of continuous flow was investigated in this study.

STUDY DESIGN AND METHODS

RBC samples were collected from nonleukoreduced (S-RBC), buffy coat-poor (BCP-RBC), and leukofiltered (LF-RBC) products at fixed time points during storage. Samples were perfused, at controlled shear stress and temperature, across a confluent endothelial cell (EC) monolayer with a parallel-flow chamber mounted to an inverted microscope. RBC-EC interactions were recorded with a digital camera attached to the microscope.

RESULTS

The number of RBCs adhering to the EC layer increased significantly with storage time in all RBC products; however, WBC reduction delayed this increase. LF-RBCs were also significantly less adherent than S-RBC or BCP-RBC products on Day 1 of storage (p < 0.05). The strength of RBC attachment to vascular endothelium was significantly stronger in S-RBC products compared to BCP-RBC and LF-RBC products.

CONCLUSION

Our findings indicate that product storage time and WBC burden increase the number and strength of adhesion of RBCs to vascular endothelium. These results may lead to greater understanding of the interaction of transfused RBCs with recipient endothelium and the biologic consequences of this adherence.

Chemokine receptors expressed on T cells in packed red blood cell units change over storage time

The transfusion of blood products is associated with adverse events that are related to the leukocytes in stored units of blood. These leukocytes have been shown to promote the elaboration of inflammatory cytokines. However, the status of a set of key inflammatory mediators, chemokine receptors, expressed on T lymphocytes in stored red blood cell (RBC) units is largely unknown. We investigated the expression pattern of selected chemokine receptors on T cells from non-leukocyte-reduced RBC units over storage time. Selecting segments from stored RBC units, we evaluated the T-cell subsets for the chemokine receptors CXCR3 and CCR4 by flow cytometry. Statistical analysis was performed by regression analysis. We analysed 30 samples stored between 5 and 38 days. The CD4+ T cells expressing CXCR3 increased by 0.27% daily (P= 0.02), whereas the expression of CCR4 declined by 0.40% daily (P < 0.001). Though the expression of the chemokine receptors on CD8+ cells followed the same trend, the changes were statistically nonsignificant. This study suggests that a longer duration of storage is associated with a higher expression of chemokine receptor CXCR3 and a lower expression of CCR4 on T cells in RBC units, suggesting a pro-inflammatory Th1 bias. The clinical significance of these changes in the setting of adverse transfusion events needs further evaluation.

Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products

Conventional neonatal cardiopulmonary bypass requires the use of large volumes of allogeneic blood to prevent unacceptable hemodilution. Evidence is accumulating to suggest that the use of blood products during cardiopulmonary bypass has a negative effect on clinical recovery through inflammatory side effects. This would suggest an advantage for eliminating blood use in infant cardiopulmonary bypass through circuit miniaturization. In this article, we review the data supporting this rationale and provide the results from studies in our laboratory that emphasize the benefits of circuit miniaturization.

Supernatant from stored red blood cell primes inflammatory cells: influence of prestorage white cell reduction

BACKGROUND

The contribution of RBC transfusion to adverse patient outcomes is controversial. There is conflicting clinical data and limited biologic data that provide an underpinning biologic rationale for any adverse impacts from RBC transfusion. This study used in-vitro measures of PMN stimulation to determine the ability of supernatant from RBCs to stimulate allogeneic WBCs and to determine the influence of residual donor WBCs and storage time on the proinflammatory potential of RBCs.

STUDY DESIGN AND METHODS

Three types of RBCs were assessed: standard non-WBC-reduced RBCs (S-RBCs), buffy coat-poor RBCs (BCP-RBCs), and prestorage WBC-filtered RBC (LF-RBCs). Supernatant was collected weekly up to Day 42 of storage. PMN priming by supernatant from RBCs was determined by three methods: induction of CD11b expression on PMNs, induction of IL-8 release from PMNs, and the chemotactic effect of supernatant on PMNs.

RESULTS

Supernatant from S-RBCs induced the expression of CD11b on PMNs, primed PMNs to release IL-8, and was chemotactic for PMNs. The magnitude of this PMN-priming progressively amplified with storage time. In contrast, supernatant from BCP-RBCs or LF-RBCs did not significantly prime PMNs. The PMN-priming effect of supernatant from RBCs correlated more closely with the level of MNCs in the RBCs than PMN content.

CONCLUSION

Supernatant from stored S-RBCs prime unstimulated allogeneic PMNs in vitro. Prestorage buffy-coat WBC reduction was as effective as WBC depletion in abrogating this proinflammatory response elicited by supernatants from RBCs. The clinical consequences, if any, of these findings for transfusion recipients are unknown.

Universal leucodepletion: an overview of some unresolved issues and the highlights of lessons learned

Universal leucodepletion (ULD) has been introduced in several countries based on the evidence that selective leucodepletion improves the clinical safety of blood components and based on animal studies that TSE infectivity is 5-7 times higher in the buffy coat than in plasma. Therefore it is perceivable that the removal of the buffy coat, by filtration, removing both leucocytes and platelets, may prove beneficial in reducing the potential risk of transmission of variant CJD by blood components. The implementation of a ULD policy has created some new requirements: Validation/standardisation of various leucodepletion processes to ensure compliance with set specifications. Standardisation/harmonisation of sampling and low leucocyte counting technologies to ensure the interchangeability of results nationally. The establishment of external quality assessment schemes on 'real' leucodepleted products where the cells come in contact with the filter matrix, to monitor the low leucocyte counting performance, nationally. Assessment of filtration-induced generation/retention of major biological response modifiers (BRM), having potential for the development of transfusion reactions. Using these approaches we have identified that, while the overall leucodepletion performance has improved following harmonisation/standardisation of the operational and counting technologies, there are still some unresolved problems and ULD alone may not provide complete protection from some viral transmission such as HTLV and CMV infections or reduction of bacterial sepsis and generation of some BRM. Moreover, ULD has not fully abrogated febrile non-haemolytic transfusion reactions (FNHTR). Therefore the key issue is not the 3-4 log(10) reduction of residual leucocytes but the design of new generation filters or leucodepletion processes with better performance characteristics, to further reduce some specific leucocyte subsets and their fragments as well as reduce the activation of coagulation/complement/kinin and inflammatory systems. Efforts should also be made to reduce the rapid development of apoptotic/necrotic cells and the residual risk associated with plasma, which often contains a vast array of BRM, responsible for residual transfusion reactions. These could only be effectively achieved by working in cooperation with the suppliers of blood component technologies. This overview briefly highlights some of the unresolved issues related to ULD, based on the experience in the UK. Technical details can be found in the reading list provided at the end.

Limited efficacy of universal leucodepletion in reducing the incidence of febrile nonhaemolytic reactions in red cell transfusions

This article demonstrates a 62% reduction in the number of febrile nonhaemolytic transfusion reactions (FNHTRs) and 50% reduction in febrile reaction rate associated with red cell transfusions following graded introduction of universal leucodepletion. Though this is a statistically significant reduction (P = 0.009), it shows limited efficacy in abrogating this complication. We also found a reduction in the proportion of cases of FNHTRs with lymphocytotoxic antibodies over the period studied from 54% in 1998, 28% in 1999 to 23% in 2000. This corresponds to a relative increase in the number of febrile reactions without human leucocyte antigen (HLA) antibodies following full implementation of universal leucodepletion, as the total number of reported reactions actually fell considerably during the period. The increase in the number of cases without HLA antibodies was directly proportional to the increase in the number of leucodepleted units used.

Cytokines as quality indicators of leucoreduced red cell concentrates

Different types of filters are currently used for leucodepletion of red cell concentrates. These filters meet the specification for leucoreduction (<5 x 10(6) leucocytes/ATD) but the quality of the final product may differ depending on the performance of the filters for effective removal of both leucocytes, platelets and possibly cytokines which are associated with transfusion reactions. We measured the levels of three representative cytokines: IL-8, RANTES and TGF-beta1 in red cell concentrates prior to and subsequent to the filtration procedure on day 1 and after a storage period of 35 days. Low levels of IL-8 (10-24 pg/ml) in the control unfiltered concentrates on day 1 which increased by approximately twofold on storage. Filtration reduced the levels of IL-8 on day 1 and day 35, in filtered concentrates in comparison with their control unfiltered counterparts. Leucoreduced concentrates produced by three different filters showed similar IL-8 levels on day 1 and day 35. However, concentrates prepared using another type of process showed a twofold increase in IL-8 levels on storage in comparison with day 1. None of the concentrates tested contained any detectable RANTES and TGF-beta1 suggesting a minimal platelet content. These results indicate that a combination of IL-8, RANTES and TGF-beta1 are useful quality indicators for validation of leucoreduced red cell preparations.

Immune response to autologous transfusion in healthy volunteers: WB versus packed RBCs and FFP

BACKGROUND

Storage of blood as packed RBCs and FFP is standard practice in allogeneic transfusion. Separation into components has been proposed for autologous transfusion, as well, but beneficial effects have not yet been shown.

STUDY DESIGN AND METHODS

Twenty-four healthy male volunteers were randomly assigned to receive 1 unit of either autologous RBCs and FFP (RCP group) or WB (WB group) after 49 or 35 days of storage, respectively. The immune response was analyzed by ELISA for IL-6, C3a, terminal complement complex SC5b-9, TNF-alpha, and neopterin. Differential WBC counts and the phagocytosis of neutrophils and monocytes were measured by flow cytometry.

RESULTS

Cell counts of monocytes (0.85 x 10(3) ng/microL) [corrected] and neutrophils (6.9 x 10(3) ng/microL) [corrected] increased 30 minutes after WB transfusion and then returned to close to the baseline values seen in the RCP group (0.47 and 2.9 x 10(3) ng/microL [corrected], respectively) throughout the monitored period (p<0.05). C3a (169 vs. 116 ng/microL) [corrected] and IL-6 (29 vs. 6 pg/mL) reached higher plasma concentrations in the WB group (n = 11) than in the RCP group (n = 10). Phagocytosis of opsonized Escherichia coli was increased in neutrophils and monocytes and lasted up to 7 days after the transfusion of whole blood.

CONCLUSION

Autologous WB induces a modest immunomodulation, but this effect is not observed upon transfusion of autologous blood components.